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Last updated February 10, 2026
Stability AI’s Stable Image Ultra is a state-of-the-art image generation model designed to create high-quality, detailed images from text prompts. It offers improved resolution, finer details, and greater consistency compared to earlier versions.
- Model ID:
stable-image-ultra - Region:
us
When to Use This Model
Stable Image Ultra is ideal for generating photorealistic images, concept art, and visual content based on text descriptions. It can be particularly useful for generating images for content like blog posts and marketing campaigns. Image generation models (including this one) are less well-suited for creating images with very specific properties. For example, current models struggle to generate images with very specific or consistent colors, numbers of objects, characters, layouts, or compositions.
Usage
Stable Image Ultra follows our Stability v1/images/generations API schema.
To provision access to the model, attach a heroku-inference addon to your app $APP_NAME:
heroku addons:create heroku-inference:standard -a $APP_NAME
You can invoke the model in various ways, see:
- Heroku CLI
aiplugin (heroku ai:models:call) - curl
- Python
- Ruby
- Javascript
Rate Limits
- Maximum requests per minute: 20
Example curl Request
Get started quickly with an example request:
export DIFFUSION_KEY=$(heroku config:get -a $APP_NAME DIFFUSION_KEY)
export DIFFUSION_URL=$(heroku config:get -a $APP_NAME DIFFUSION_URL)
curl $DIFFUSION_URL/v1/images/generations \
-H "Authorization: Bearer $DIFFUSION_KEY" \
-d @- <<EOF | jq -r '.data[0].b64_json' | base64 --decode > "x.png"
{
"model": "stable-image-ultra",
"prompt": "A surreal landscape with glowing mushrooms under a night sky.",
"aspect_ratio": "16:9",
"output_format": "png",
"seed": 12345,
"negative_prompt": "crowded, noisy, chaotic"
}
EOF
open x.png